Conventionally, an information wiring system using a twisted-pair cable has been widely used in an office or in a factory to transmit different kinds of information such as an audio signal, a digital signal for LAN, and a picture signal. In this connection, a twisted-pair cable around which a shield is not applied is referred to as a UTP (Unshielded Twisted-Pair) cable. The UTP cable has been normally used for a LAN application of Ethernet (Registered Trademark) which is not asked for performing a high speed transmission, especially by virtue of easy handling and low cost thereof, in addition to a telephone line and the Ethernet (Registered Trademark). In such an information wiring system, it has been used a junction terminal board to support a wiring work of network called as a patch panel in preparation for a case where a change in the information wiring is needed due to a layout change in office.
Specifically, a patch panel to which a modular adapter for telephone disclosed in the PATENT LITERATURE 1 is attached is publicly known. The patch panel is configured by mounting four mounting frames (cover serving as holding member) which hold side by side in a row six modular adapters (twenty-four modular adapters in total) to which a modular plug is removably connected, and by installing the patch panel in a fixed part such as a rack.
When the mounting frames, to which the modular adapter is attached, are mounted on the patch panel, the mounting frames are first tilted and inserted from the front side into a window opening formed in the patch panel. Then, when a projection which is provided in a protruding manner on an abutting piece provided on the inside of a lower edge part of the mounting frames is inserted into a through hole of the patch panel, an opening edge of the through hole is clamped in a groove between the front of the mounting frames and the projection. After that, when an upper part of the mounting frames is inserted into the window opening of the patch panel, with the opening edge as an axis, a fitting claw which is provided in a protruding manner on an upper surface of an end of an engaging piece provided toward the inside of an upper edge part of the mounting frames abuts against the opening edge of the patch panel, and is downwardly pressed and bent. Thereafter, the fitting claw crosses over the opening edge to engage with the back side of the window opening, and is fixed to the window opening of the patch panel.
Meanwhile, when the mounting frames are unmounted from the patch panel, a tip of a tool such as a flathead screwdriver is inserted between a tool insertion groove formed in the front of the mounting frames and a recess formed in the patch panel, and then a downward force is applied to the engaging piece. This releases the fitting state between the fitting claw and the opening edge, thereby unmounting the mounting frames from the patch panel.